#include "FoGGEDEF.h"
#include "GeneralHashFunctions.h"



namespace _FOGGE_
{
	namespace _UTIL_
	{

		namespace _HELPER_
		{

			
			HASHFUNCTION DefaultHashFunction=_HASH_::ELFHash;

			namespace _HASH_
			{
				unsigned int RSHash(const foString& str)
				{
				   unsigned int b    = 378551;
				   unsigned int a    = 63689;
				   unsigned int hash = 0;

				   for(std::size_t i = 0; i < str.length(); i++)
				   {
					  hash = hash * a + str[i];
					  a    = a * b;
				   }

				   return hash;
				}
				/* End Of RS Hash Function */


				unsigned int JSHash(const foString& str)
				{
				   unsigned int hash = 1315423911;

				   for(std::size_t i = 0; i < str.length(); i++)
				   {
					  hash ^= ((hash << 5) + str[i] + (hash >> 2));
				   }

				   return hash;
				}
				/* End Of JS Hash Function */


				unsigned int PJWHash(const foString& str)
				{
				   unsigned int BitsInUnsignedInt = (unsigned int)(sizeof(unsigned int) * 8);
				   unsigned int ThreeQuarters     = (unsigned int)((BitsInUnsignedInt  * 3) / 4);
				   unsigned int OneEighth         = (unsigned int)(BitsInUnsignedInt / 8);
				   unsigned int HighBits          = (unsigned int)(0xFFFFFFFF) << (BitsInUnsignedInt - OneEighth);
				   unsigned int hash              = 0;
				   unsigned int test              = 0;

				   for(std::size_t i = 0; i < str.length(); i++)
				   {
					  hash = (hash << OneEighth) + str[i];

					  if((test = hash & HighBits)  != 0)
					  {
						 hash = (( hash ^ (test >> ThreeQuarters)) & (~HighBits));
					  }
				   }

				   return hash;
				}
				/* End Of  P. J. Weinberger Hash Function */


				unsigned int ELFHash(const foString& str)
				{
				   unsigned int hash = 0;
				   unsigned int x    = 0;

				   for(std::size_t i = 0; i < str.length(); i++)
				   {
					  hash = (hash << 4) + str[i];
					  if((x = hash & 0xF0000000L) != 0)
					  {
						 hash ^= (x >> 24);
					  }
					  hash &= ~x;
				   }

				   return hash;
				}
				/* End Of ELF Hash Function */


				unsigned int BKDRHash(const foString& str)
				{
				   unsigned int seed = 131; // 31 131 1313 13131 131313 etc..
				   unsigned int hash = 0;

				   for(std::size_t i = 0; i < str.length(); i++)
				   {
					  hash = (hash * seed) + str[i];
				   }

				   return hash;
				}
				/* End Of BKDR Hash Function */


				unsigned int SDBMHash(const foString& str)
				{
				   unsigned int hash = 0;

				   for(std::size_t i = 0; i < str.length(); i++)
				   {
					  hash = str[i] + (hash << 6) + (hash << 16) - hash;
				   }

				   return hash;
				}
				/* End Of SDBM Hash Function */


				unsigned int DJBHash(const foString& str)
				{
				   unsigned int hash = 5381;

				   for(std::size_t i = 0; i < str.length(); i++)
				   {
					  hash = ((hash << 5) + hash) + str[i];
				   }

				   return hash;
				}
				/* End Of DJB Hash Function */


				unsigned int DEKHash(const foString& str)
				{
				   unsigned int hash = static_cast<unsigned int>(str.length());

				   for(std::size_t i = 0; i < str.length(); i++)
				   {
					  hash = ((hash << 5) ^ (hash >> 27)) ^ str[i];
				   }

				   return hash;
				}
				/* End Of DEK Hash Function */


				unsigned int BPHash(const foString& str)
				{
				   unsigned int hash = 0;
				   for(std::size_t i = 0; i < str.length(); i++)
				   {
					  hash = hash << 7 ^ str[i];
				   }

				   return hash;
				}
				/* End Of BP Hash Function */


				unsigned int FNVHash(const foString& str)
				{
				   const unsigned int fnv_prime = 0x811C9DC5;
				   unsigned int hash = 0;
				   for(std::size_t i = 0; i < str.length(); i++)
				   {
					  hash *= fnv_prime;
					  hash ^= str[i];
				   }

				   return hash;
				}
				/* End Of FNV Hash Function */


				unsigned int APHash(const foString& str)
				{
				   unsigned int hash = 0;

				   for(std::size_t i = 0; i < str.length(); i++)
				   {
					  hash ^= ((i & 1) == 0) ? (  (hash <<  7) ^ str[i] ^ (hash >> 3)) :
											   (~((hash << 11) ^ str[i] ^ (hash >> 5)));
				   }

				   return hash;
				}
				/* End Of AP Hash Function */
			}
		}
	}
}
